This invention relates to asphalt-concrete paving. In one of its aspects this invention relates to the stabilization of open graded surface asphalt-concrete courses. In another of its aspects this invention relates to preventing lateral displacement of a paved surface under a moving load.
An open graded course of an asphalt-cement aggregate mix is a thin, porous layer of aggregate one-half inch to two inches, more commonly three-fourth inch to one and one-half inches, thick after compaction, designed to allow rapid drainage of rain water from a paved surface. Since this surface is especially designed to prevent the buildup of water layers which might lead to hydroplaning conditions, these surfaces are usually found on roadways but are more especially useful in airport aprons and runways.
These pavements have intersticial voids and are not as compact as the underlying bearing surface so that the impact and rolling motion of a large vehicle, such as a large plane, tend to displace the open graded overlay thereby producing hills and valleys along a paved area such as a runway or airport apron. This can become a problem on roadways at intersections where large trucks are caused to stop but is an especially aggravated problem in the turning area of multi-wheeled planes. We have found that the problem of lateral displacement or "shoving" of an asphalt-concrete course under a moving load can be alleviated by a two-step treatment of an open graded course of an asphalt-cement aggregate either at the time of construction or after the pavement is set and a problem of displacement has been noticed.
Other aspects and the several advantages of this invention will be apparent to those skilled in the art upon reading the disclosure and the appended claims to this invention.